Modification of suitable electrolytes for high-voltage lithium-rich manganese-based cathode with wide-temperature range

Abstract

New high-voltage cathode materials have been gradually developed, and their discharge voltages can reach more than 5 V ( vs. Li+/Li), but there are very few electrolytes matched with this cathode. Here, we have designed a modi ed electrolyte containing both FEC and LiDFOB additives which has a high oxidation potential over 5.0V, which perfectly match for high voltage lithium-rich manganese-based cathode. When FEC and LiODFB were added to the basic electrolyte, at 25℃ and 40℃ lithium-rich manganese-based cathode has excellent cycling stability in the voltage range of 2.5-5V. The capacity retention rate of the LMR/Li battery after 200 cycles was 66.5% at 25°C, and 68.7% after 100 cycles at 40°C. The rst cycle discharge speci c capacity of each system exceeds 200 mAh/g. In contrast, the capacity retention rate of lithium-ion batteries using primary electrolyte is merely 53.6% and 67.6% after cycling at 25 °C and 40 °C. The high-temperature, high-voltage performance exhibited by this formulation is a perfect match for Li-rich manganese-based cathode materials. Highlights 1. Li-rich Mn-based, excellent performance at high voltage and temperature.2. FEC, high oxidation stability, inhibit the side reaction of the electrolyte.3. LiDFOB, promote a stable and low-resistance CEI lm at the interface. 4. FEC+LiDFOB, synergistic effect at high-voltage, improves high-voltage stability.